[Bug fortran/52393] I/O: "READ format" statement with parenthesed default-char-expr

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52393

--- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> The code in #5 is missing the initial parenthesised expression that exposes
> the flaw in parsing logic - the left hand operand of the string concatenation
> needs to be `('(')`, and not just the string literal.

Indeed! Note that gfortran accepts '(' // ('A)'), or ('(' // 'A)'). AFAICT the
problem occurs only when the first substring is enclosed in parentheses.